The major objective of this pilot study is to examine the hypothesis that schizophrenic patients with a family history of affective disorders constitute a neurobiologically discrete subgroup of the schizophrenic syndrome, and may manifest neuroendocrine and sleep abnormalities similar to those seen in affective disorders. We plan to study a group of schizophrenic patients diagnosed by RDC criteria with family histories of major depressive disorder or bipolar disorder in a first degree relative (Group 1: n=15) and compare them with a group of similarly diagnosed schizophrenic patients with a history of schizophrenic illness in a first degree relative (Group 2: n-15), with respect to the following parameters: a) Two neuroendocrine test known to be frequently abnormal in affective disorders, namely the Dexamethasone Suppression Test (DST) and the Thyrotropin Releasing Hormone (TRH) Challenge Test and, b) Sleep Polysomnographic Records. The specific hypothesis tested in this study is that Group 1 will show dexamethasone nonsuppression, blunted TSH responses to TRH, and abnormally short Rapid Eye Movement (REM) sleep latency more frequently than Group 2. The findings of this study are likely 1) to help delineate aetiologically meaningful subgroups within the heterogeneous schizophrenic syndrome and, 2) to help identify specific subgroups that may differ in treatment responsiveness and prognosis.